"Ground quality" is a continuum. Leg caps or boots can frequently be compromised, and stage decking gets banged around all the time. Aluminum Oxide cannot be depended on in any fashion as an insulator. Bottom line - you have to assume that in the absence of intentional insulators, any metal is conductive and potentially able to be energized. The larger the metal and/or the larger the contact area with the ground, the larger the current potential. There's nothing magic about a 6' or 8' ground rod in the ground - a few legs of an aluminum stage with compromised feet on wet grass may have a lower-impedance ground connection than an intentional ground rod in drier soil.
My language may not have been precise enough to fully explain this - an unfortunate reality of this not being billable time. Two points here that could be expanded on later:
GFCIs absolutely need a ground connection to function. This is implemented by the G->N bond in the service entrance, which has the function of completing the circuit of the earth back to the neutral wire. This is required, otherwise if you touch the hot terminal of your GFCI protected outlet and ground, there is no completed circuit path for the leakage current to go - your body and the ground you're standing on (or the generator, depending on your perspective) would just float at the potential of the hot wire. This is exactly the isolating scenario of the 120v only Honda Generators I mentioned - a GFCI would never trip, as there is nowhere else for the current to go, since the only possible current sink is the neutral wire.
Note 1: A GFCI receptacle itself does not necessarily need to be grounded - they are often used to retrofit homes with no ground wire at the receptacle, however the GFCI depends on the environment - the house, stage, etc., being bonded to neutral (done at the service entrance) for there to be a leakage current sink back to the panel.
Note 2: The intent of a GFCI receptacle is to provide a measure of life safety for currents that leak from hot to ground. A GFCI receptacle provides no safety for a hot -> neutral fault.
Point 2 (Re: in a shore power situation are bonding and grounding the same thing):
From a cord and plug device standpoint, yes. The green wire in the cord provides the path to earth ground as well as the bonded path back to neutral. I used the language I did because in the example of staging given, some may think it would be acceptable to drive a ground rod in at the stage and then it would be "grounded". This is inadequate, as there needs to be a low-impedance path from the conductive stage back to the G/N bond point at the service entrance to sink fault currents sufficiently well to trip the OCPD. This, functionally, is bonding - accomplished with a ground wire.
I don't understand your third point question, but absolutely the stage deck should be grounded and bonded in a shore power situation, or any time you have more than a single circuit generator.
Thanks TJ - my apologies for picking apart the language so literally - I do appreciate all I learned in this discussion and that you were spending your personal (non-billable) time.
I also did quite a bit of additional reading in the interim - "No Shock Zone" (Thanks Mike Sokol), and Phil Graham's three-part article in FOH Online. http://www.fohonline.com/current-issue/74-tech-feature/8858-generators-and-portable-primer-part-1.html
Through your efforts and theirs, I have a much better understanding of grounding vs bonding - the ground rod vs the low impedance path back to the panel needed to trip a breaker and provide safety.
I also have a better handle on the Honda Gen floating neutral/ground issues. (so I won't be bugging you here). Still much to read and to sort out. Thought I had a good handle on it, but it seems I have only scratched the surface.
As for the "ground quality" vis a vis aluminum oxide as an insulator - you're absolutely correct - trust aluminum oxide or a vinyl boot cap as insulators to keep us safe? Never. I was looking at these things not as a "protection from ground" but as an interference - high resistance point that could interfere with earth-ground quality.
I guess I had better start drafting a letter to the city manager...
- Speak in broad terms of electrical safety and the likelihood that the stage could become energized
- Refer them to Salina, Kansas
- Get their electrician to produce a plan and get that to the maintenance men who put the stage up.
It's a start...
And again, Thanks TJ!